Geochronology and tectonics of the northern Wolverine Complex, British Columbia

1979 ◽  
Vol 16 (7) ◽  
pp. 1428-1438 ◽  
Author(s):  
Randall R. Parrish
Keyword(s):  
British Columbia ◽  
Late Jurassic ◽  
Blocking Temperature ◽  
Mountain Area ◽  
North Central ◽  
Geothermal Gradients ◽  
Clastic Rocks ◽  
The North ◽  
Uplift Rates ◽  
Uplift And Erosion

The Wolverine Complex is a metamorphosed and polydeformed sequence of Hadrynian clastic rocks that forms part of the Omineca Crystalline Belt in north-central British Columbia. Twenty-six Rb–Sr and K–Ar dates from an area at the north end of the complex are presented. Rb–Sr muscovite dates are the oldest, 70–166 Ma, and constrain the main metamorphic–deformational event to the Middle to Late Jurassic or earlier. K–Ar dates on muscovite and biotite are highly discordant and the dates of the minerals vary in the order Rb–Sr muscovite > K–Ar muscovite > K–Ar biotite. Many rocks show partial or complete homogenization of the isotopes during an early Tertiary thermal event, which has extensively reset K–Ar dates in part of the complex.The blocking temperatures of the isotopic systems when combined with the isotopic dates, other published dates, and estimated geothermal gradients, allow inference of thermal history and paleo-uplift rates. In the Chase Mountain area where the influence of Eocene resetting is either small or minimal, the rocks had cooled to 220 ± 40 °C by about 80 Ma ago or earlier. During their cooling from metamorphic temperatures of about 500 °C, they cooled at rates between 3 and 10 °C/Ma with an average minimum cooling rate of 4 °C/Ma. Using estimated geothermal gradients, corresponding uplift rates were 0.1–0.3 km/Ma or more.Because cooling of these rocks probably took place dominantly by advection resulting from uplift and erosion, a significant portion of the total uplift of these rocks was complete by the time they reached the biotite blocking temperature, 220 °C, at least 80 Ma ago. The predominantly Late Jurassic to Early Cretaceous uplift of the complex implied by these dates has important implications for regional tectonics and models of evolution for the Omineca Crystalline Belt and adjacent areas.

Jura-Cretaceous (Oxfordian to Cenomanian) stratigraphy of the north-central Bowser Basin, northern British Columbia

1989 ◽  
Vol 26 (5) ◽  
pp. 1001-1012 ◽  
Author(s):  
H. O. Cookenboo ◽  
R. M. Bustin
Keyword(s):  
British Columbia ◽  
Lower Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Upper Jurassic ◽  
Thick Section ◽  
North Central ◽  
The North

Three new formations of Late Jurassic and Early to mid-Cretaceous age are defined for a 2000 m thick section of Jura-Cretaceous rocks exposed in the north-central Bowser Basin. The Currier Formation (Oxfordian to Kimmeridgian or Tithonian) consists of 350–600 m of interbedded shales, siltstones, sandstones, coals, and carbonates. The McEvoy Formation (Barremian to as young as Albian) consists of 400–800 m of siltstones and shales with minor sandstones, thin coals, limestones, and conglomerates. The Devils Claw Formation (in part mid-Albian to Cenomanian) consists of 300–600 m of strata characterized by thick pebble and cobble conglomerates, with associated coarse sandstones and minor siltstones and shales.Two successive coarsening-upward sequences are identified in the study area. The first begins with Middle Jurassic marine shales of the Jackson unit grading upwards to coarser Upper Jurassic facies of the Currier Formation. The Currier Formation is conformably or unconformably overlain by siltstones and shales of the Lower Cretaceous McEvoy Formation, which forms the base of a second coarsening-upward sequence. Conglomerates appear with increasing frequency in the upper McEvoy and are the dominant lithology of the overlying Devils Claw Formation. The contact between the McEvoy and Devils Claw formations is gradational. The Devils Claw Formation forms the top of the second coarsening-upward sequence.The Currier Formation (Late Jurassic) is equivalent to the upper units of the Bowser Lake Group. The McEvoy and the Devils Claw formations (Barremian to Cenomanian) are coeval with the Skeena Group (Hauterivian? to Cenomanian). A probable unconformity separating the Upper Jurassic Currier Formation from the Lower Cretaceous McEvoy Formation correlates with a hiatus in the southern Bowser Basin and probably represents a regional unconformity.

Nina Creek Group and Lay Range Assemblage, north-central British Columbia: remnants of late Paleozoic oceanic and arc terranes

1997 ◽  
Vol 34 (6) ◽  
pp. 854-874 ◽  
Author(s):  
Filippo Ferri
Keyword(s):  
British Columbia ◽  
North America ◽  
Volcanic Rocks ◽  
Tholeiitic Basalt ◽  
Ocean Floor ◽  
North Central ◽  
Marginal Basin ◽  
The North ◽  
Lower Division ◽  
Ocean Ridge

In north-central British Columbia, a belt of upper Paleozoic volcanic and sedimentary rocks lies between Mesozoic arc rocks of Quesnellia and Ancestral North America. These rocks belong to two distinct terranes: the Nina Creek Group of the Slide Mountain terrane and the Lay Range Assemblage of the Quesnel terrane. The Nina Creek Group is composed of Mississippian to Late Permian argillite, chert, and mid-ocean-ridge tholeiitic basalt, formed in an ocean-floor setting. The sedimentary and volcanic rocks, the Mount Howell and Pillow Ridge successions, respectively, form discrete, generally coeval sequences interpreted as facies equivalents that have been interleaved by thrusting. The entire assemblage has been faulted against the Cassiar terrane of the North American miogeocline. West of the Nina Creek Group is the Lay Range Assemblage, correlated with the Harper Ranch subterrane of Quesnellia. It includes a lower division of Mississippian to Early Pennsylvanian sedimentary and volcanic rocks, some with continental affinity, and an upper division of Permian island-arc, basaltic tuffs and lavas containing detrital quartz and zircons of Proterozoic age. Tuffaceous horizons in the Nina Creek Group imply stratigraphic links to a volcanic-arc terrane, which is inferred to be the Lay Range Assemblage. Similarly, gritty horizons in the lower part of the Nina Creek Group suggest links to the paleocontinental margin to the east. It is assumed that the Lay Range Assemblage accumulated on a piece of continental crust that rifted away from ancestral North America in the Late Devonian to Early Mississippian by the westward migration of a west-facing arc. The back-arc extension produced the Slide Mountain marginal basin in which the Nina Creek Group was deposited. Arc volcanism in the Lay Range Assemblage and other members of the Harper Ranch subterrane was episodic rather than continuous, as was ocean-floor volcanism in the marginal basin. The basin probably grew to a width of hundreds rather than thousands of kilometres.

Biochronology of selected Bowser Basin strata; tectonic significance

1988 ◽  
Vol 25 (10) ◽  
pp. 1571-1578 ◽  
Author(s):  
I. W. Moffat ◽  
R. M. Bustin ◽  
G. E. Rouse
Keyword(s):  
British Columbia ◽  
Late Jurassic ◽  
Plant Succession ◽  
Fossil Plant ◽  
North Central ◽  
Eastern Margin ◽  
Time Period ◽  
Tectonic Significance ◽  
Age Range ◽  
Recent Evaluation

Recent evaluation and reinterpretation of fossil floral and faunal data more clearly define the ages of strata exposed in the Groundhog Coalfield and the surrounding Bowser Basin of north-central British Columbia. In the Groundhog Coalfield, Bowser Lake Group strata consist of an overall coarsening-upwards cycle divisible into four informal stratigraphic units, which are, from oldest to youngest, the Jackson, Currier, McEvoy, and Devils Claw units. The section has an unconformable relationship with underlying Bajocian Spatsizi marine shales, volcanics, and arenaceous sediments. Marine macrofossils indicate a Callovian to Oxfordian age for the Jackson unit. The fossil plant succession present in the overlying Currier unit indicates Late Jurassic affinities. Recent unpublished palynologic data from lower McEvoy rocks in the northern Groundhog Coalfield suggest a Barremian age. The palynoassemblage present in the lower Devils Claw unit in the central part of the Groundhog Coalfield suggests a late middle Albian age.Rocks of the Sustut Group have an angular unconformable relationship with underlying Bowser Lake Group strata near the eastern margin of the Bowser Basin. The palynoassemblage present in Sustut Group rocks from the southern Sustut Basin suggests a Campanian to Maastrichtian age range, in contrast to a probable late Albian to Campanian age range for the northern Sustut Basin and a middle to late Albian age from Sustut Group outliers present within the northern Bowser Basin. Within the Groundhog Coalfield, Devils Claw strata have a conformable or paraconformable relationship with underlying Bowser Lake Group strata.Regional discrepancy in the age and geometry of the sub-Sustut unconformity is attributed to a time-transgressive unconformity that resulted from cratonward advance of an isostatically induced peripheral bulge. Age and contact relationships suggest that deformation in the Bowser Basin and surrounding Sustut Basin must have spanned the time period that corresponds to a second uplift pulse of the Columbian orogen (Aptian to early Cenomanian) and the uplift pulse related to the Laramide orogen (Campanian to Maastrichtian).

Controls on the preservation of Jurassic volcanism in the Northern Carnarvon Basin

2021 ◽  
Vol 61 (2) ◽  
pp. 600
Author(s):  
Michael Curtis ◽  
Simon Holford ◽  
Mark Bunch ◽  
Nick Schofield
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
Volcanic Centre ◽  
North West ◽  
The North ◽  
Igneous Provinces ◽  
Australian Continent ◽  
Northern Carnarvon Basin ◽  
Uplift And Erosion ◽  
Carnarvon Basin

The Northern Carnarvon Basin (NCB) forms part of the North West Australian margin. This ‘volcanic’ rifted margin formed as Greater India rifted from the Australian continent through the Jurassic, culminating in breakup in the Early Cretaceous. Late Jurassic to Early Cretaceous syn-rift intrusive magmatism spans 45000km2 of the western Exmouth Plateau and the Exmouth Sub-basin; however, there is little evidence of associated contemporaneous volcanic activity, with isolated late Jurassic volcanic centres present in the central Exmouth Sub-basin. The scarcity of observed volcanic centres is not typical of the extrusive components expected in such igneous provinces, where intrusive:extrusive ratios are typically 2–3:1. To address this, we have investigated the processes that led to the preservation of a volcanic centre near the Pyrenees field and the Toro Volcanic Centre (TVC). The volcanic centre near the Pyrenees field appears to have been preserved from erosion associated with the basin-wide KV unconformity by fault-related downthrow. However, the TVC, which was also affected by faulting, is located closer to the focus of regional early Cretaceous uplift along the Ningaloo Arch to the south and was partly eroded. With erosion of up to 2.6km estimated across the Ningaloo Arch, which, in places, removed all Jurassic strata, we propose that the ‘Exmouth Volcanic Province’ was originally much larger, extending south from the TVC into the southern Exmouth Sub-basin prior to regional uplift and erosion, accounting for the ‘missing’ volume of extrusive igneous material in the NCB.

On the land mammals of the Queen Charlotte Islands, British Columbia, by John Henry Keen, with a catalogue of specimens

2017 ◽  
Vol 44 (2) ◽  
pp. 259-274 ◽  
Author(s):  
S. G. Sealy
Keyword(s):  
British Columbia ◽  
Natural History ◽  
The United States ◽  
Haida Gwaii ◽  
North Central ◽  
Queen Charlotte Islands ◽  
The North ◽  
Annotated List ◽  
History Of ◽  
Evolution Of Mammals

From 1890 to 1899, the Reverend John Henry Keen collected plants and animals in the vicinity of the Anglican mission at Massett, on the north-central coast of the Queen Charlotte Islands (Haida Gwaii), British Columbia, Canada. Keen's prodigious collecting efforts resulted in the first detailed information on the natural history of that region, particularly of the beetle fauna. Keen also observed and collected mammals, depositing specimens in museums in Canada, England and the United States, for which a catalogue is given. Several mammal specimens provided the basis for new distributional records and nine new taxa, two of which were named for Keen. In 1897, Keen prepared an annotated list of ten taxa of land mammals of the Queen Charlotte Islands, including the first observations of natural history for some of the species. Particularly important were the insightful questions Keen raised about the evolution of mammals isolated on the Islands, especially why certain species, abundant on the mainland, were absent.

Engelmann × Sitka spruce hybrids in central British Columbia

1989 ◽  
Vol 19 (9) ◽  
pp. 1190-1193 ◽  
Author(s):  
G. K. Kiss
Keyword(s):  
British Columbia ◽  
Sitka Spruce ◽  
North Central ◽  
The North ◽  
Plantation Age ◽  
The Difference ◽  
Total Tree ◽  
Hybrid Spruce

Several crosses of Engelmann × Engelmann and Engelmann × Sitka spruce (one parent) were studied. Average crossability of the latter was 24.5%. Average heights of the pure Engelmann and the hybrid spruce were 361.6 and 183.6 cm, respectively, at plantation age 13 (16 years from seed). The difference in height appeared to be the result of repeated winter kill of large proportions of the previous summer's growth. Age to age correlations for total tree heights at 3–7 and 7–13 years old were highly significant. Based on these results, Engelmann × Sitka spruce hybrids are not recommended for reforestation purposes in the north-central interior of British Columbia. However, there are indications that preselecting better genotypes may improve the performance of the resulting hybrids; thus, further research in this direction is warranted.

THE EUROPEAN SKIPPER, THYMELICUS LINEOLA (LEPIDOPTERA: HESPERIIDAE), IN MANITOBA AND NORTHWESTERN ONTARIO

1981 ◽  
Vol 113 (12) ◽  
pp. 1123-1124 ◽  
Author(s):  
W. B. Preston ◽  
A. R. Westwood
Keyword(s):  
United States ◽  
British Columbia ◽  
Nova Scotia ◽  
North America ◽  
New Brunswick ◽  
Present Note ◽  
North Central ◽  
The North ◽  
Northwestern Ontario ◽  
Central United States

The spread of Thymelicus lineola (Ochsenheimer) in North America has been extensively documented (Rawson 1931; Clench 1956; Pengelly 1961; Arthur 1966; Burns 1966; McNeil et al. 1975; McNeil and Duchesne 1977). In Canada, T. lineola has been recorded from British Columbia, Ontario, Quebec, New Brunswick, Nova Scotia, Newfoundland, and now Manitoba (Gregory 1975; Jackson 1978). In the north central United States T. lineola has been recorded from St. Louis Co. and International Falls, Minnesota (Brewer 1977; Lundeen 1980). Pengelly (pers. comm.) observed T. lineola at Dryden, Ontario in 1972. McCabe and Post (1977) did not include this species in their list for North Dakota. The purpose of the present note is to report on the presence and collections of T. lineola in Manitoba and in northwestern Ontario.

scholarly journals Late-autumn record of Little Brown Myotis (Myotis lucifugus) in north-central British Columbia

2020 ◽  
Vol 134 (3) ◽  
pp. 248-251
Author(s):  
Roy V. Rea ◽  
Candyce E. Huxter
Keyword(s):  
British Columbia ◽  
Myotis Lucifugus ◽  
Fraser River ◽  
North Central ◽  
Late Autumn ◽  
Far North ◽  
North Shore ◽  
The North ◽  
Myotis Myotis ◽  
Scientific Value

Little Brown Myotis (Myotis lucifugus) inhabits north-central British Columbia (BC), but its flight activity at the onset of hibernation is not well known. On 31 October 2019, we saw three bats flying in patterns that suggested feeding, near the north shore of the Fraser River near Prince George, BC. Observations of Little Brown Myotis flying this late in the autumn have not previously been documented this far north in interior BC. We photographed the bats, and here we describe the encounter and discuss the scientific value of our observation.

Tectonic Overprinting near Ware, Northern Rocky Mountain Trench

1972 ◽  
Vol 9 (7) ◽  
pp. 903-913 ◽  
Author(s):  
G. H. Eisbacher
Keyword(s):  
Late Cretaceous ◽  
Late Jurassic ◽  
Upper Cretaceous ◽  
Sedimentary Rocks ◽  
Rocky Mountain ◽  
Normal Faulting ◽  
North Central ◽  
The Core ◽  
The North ◽  
Central Cordillera

Mapping in the core of the north–central Cordillera of British Columbia has revealed a system of relatively closely spaced steeply dipping faults cutting across an earlier penetrative fabric consisting of recumbent folds and intensely cleaved sedimentary rocks. The earlier (Mid – Late Jurassic) penetrative deformation was separated from the later (Late Cretaceous – Tertiary) deformation by regional uplift, normal faulting, and initiation of intermontane deposition. The Upper Cretaceous – Lower Tertiary Sifton Formation was involved only in the later deformational pulse. Kink folding and oblique faulting are the principal mechanisms of the later pulse. The orientation of principal regional contraction changed from an early WSW–ENE direction to a late SSW–NNE direction. From this it is inferred that some of the young lineaments along and near the Rocky Mountain Trench are probably oblique–slip faults with unknown, but probably small right–lateral slip components.

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